Ninja 600 - re-projecting

Hi all. I'm new here and new to EVs, but since I've already been trolling I thought I'd drop a post and say hi.

I've built a couple of cafe racers over the last few years, and I've been thinking about an electric conversion for a while. I just picked up a bike off Craigslist that's already been converted, but has no batteries, BMS or charger. It's running an Alltrax 7245 and ME0709 motor. It has a contactor and DC-DC, and some sort of speedo and possibly ammeter, I haven't figured it out yet. It's running about 5:1 drive ratio, but needs a chain. Oh, and it's pretty ugly! It was running SLABs, but I think I'll save my pennies and go lithium something-or-other, possibly Leaf cells. Then have to get a BMS and charger... I think I'll probably spend the rest of the summer and winter (along with other projects) getting it a little prettier, and aim to get a battery to have it running for next summer.

Okay, I'm starting to gain a little momentum. I was going to let it fester for the rest of the summer, but I want to see this thing go!

I just pulled the trigger on 11 Leaf modules from Hybrid Auto Centre, so things are about to get real! They certainly already have for my bank account...

Judging from what I've read here (thanks again), the Alltrax 7245 is good for up to 90v, so I'll either slightly underchage the battery, or just use 'half' of the last module, so leave out one in-parallel cell pair. My plan is to start getting the modules mounted while I figure out what, if anything, I want to do for a BMS. I'd rather have a BMS, even if it's just something simple like a miniBMS, but that's probably a topic for another thread...

My problem at the moment is one of charging. The bike came with a Zivan NG1, but I'd pretty-much written it off because it's programmed for LA's, and because the previous owner said it didn't actually work. I sent an enquiry to Electric Conversions in Sacremento, and they said they could repair and reprogram it for me for $130-$170 USD, so that seeme like a good option. The problem I have is that they want me to 'please include which of the attached curves you would prefer', when I send it in, choosing from the two documents here (I had to zip them or they were too big to upload): Algorithms 500.zip

I think that 519a is the one to go for, because it's the only one with a max/ending voltage of 4.2V matching the leaf cell voltage, but I'm not sure. I read somewhere that the LMO cells are charged at a voltage equal to the max terminal voltage, so that would seem to fit... Also, if I'm aiming for less than 90V max, 10.5 modules at 4.2V/module would give 88.2V, so that would seem to be a good max charge for the pack. Does that sound right? I guess the other option is to use all cells and just undercharge the whole pack, but that seems messy. Would it be better though? I kinda like the idea of having a 'spare' cell, but it's probably not necessary.

I don't understand how you plan on splitting the last module. I haven't bought mine yet, so I'm of no help to you, sorry. I was planning on using 11, and undercharging the entire pack, which should help extend the life of the pack. it's looking like I'm going to have to wait another year

The three terminals on the module give you access to the two in-parallel pairs of cells in the module. The two outside terminals are for the whole module, so all four cells - the voltage of two cells in series, and the inside terminal is where the in-parallel pairs are connected in series, so connecting between that and either outside terminal will give you the voltage of one cell.

That middle 4 millimeter bolt terminal is for BMS, not pulling traction current through. I wouldn't assume it could handle the load. You'd probably need to do surgery on the module to get a beefier connection. Without a BMS you definitely want to charge to less than 4.2 volts per cell. Run the 11 modules, and charge to 88.0-90.2 volts max. That is 4.0-4.1 per cell, and just before the voltage curve goes vertical. If you go for 4.2 without a BMS you will end up cooking cells. Having the extra cell will just make it easier on the pack.

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I concur, run all 11 modules and under charge a bit (with or without BMS). Charge to whatever max your controller will accept. ≈ 90v for an Alltrax.

Although I think Mini BMS has a non-adjustable cut off at 4.2, you could still charge to 90v and have the 4.2v HV cutoff from the BMS as a safety, but you would have to end the charge with the charger voltage, not the bms.

Next time I am visiting my Brother in Chiliwack maybe I can stop by and check it out!